Smoke detector



FIG. 1 is a front, top and right side perspective view of a smoke detector showing our new design;

FIG. 2 is a rear elevational view thereof with the smoke detector inverted;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a left side elevational view with the smoke detector upended;

FIG. 5 is a right side elevational view thereof in the position of FIG. 4; and

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a smoke detector, as shown. 